Revenue, Deferred Revenue And Prepaid Commissions - Prepaid Commissions (Details) - Prepaid Commissions $ in Thousands	3 Months Ended
Mar. 31, 2019 USD ($)
Capitalized Contract Cost [Roll Forward]
December 31, 2018	$ 2,394
Additions	(1,553)
Commissions Recognized	1,424
March 31, 2019	$ 2,265

Amount, after accumulated amortization and accumulated impairment loss, of asset recognized from cost incurred to obtain or fulfill contract with customer.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 340
-SubTopic 40
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=68051541&loc=SL49131252-203054

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant